Guidelines for the characterization of metal halide nanocrystals

Metal halide (MH) nanocrystals are mainly studied for their optical emission properties. Given the several possible variants in terms of structure, composition, and doping, many MH materials (and the corresponding nanocrystals) remain to be uncovered. The soft character of MH lattices renders their characterization rather complicated; hence, a broad array of characterization techniques must be used. This is even more critical when a new compound, with an unknown crystal phase, is made in the form of nanocrystals, thus requiring a structural solution. The combination of various structural, compositional, morphological, spectroscopic, and surface characterization techniques must be complemented by realistic theoretical models of nanocrystals that include explicitly the surface through a correct termination of the material and the presence of ligands, for a complete picture of the system. The family of metal halide (MH) nanocrystal materials is still vastly unexplored and unlocking their full potential is just at the beginning. The understanding and, therefore, the optimization of the properties of these nanoscale systems passes through a series of experimental characterization techniques that span compositional analysis, resolution of unknown (nano)crystal phases, determination of the nanocrystal facets, assessment of ligands bound to the surface, and analysis of the optical properties. All of these characterizations, in turn, require specific advanced tools. The data collected are complemented by computational models to attain a complete picture of a given system. Here, we highlight the best practices for the application of these techniques, also based on the expertise developed in our groups. The family of metal halide (MH) nanocrystal materials is still vastly unexplored and unlocking their full potential is just at the beginning. The understanding and, therefore, the optimization of the properties of these nanoscale systems passes through a series of experimental characterization techniques that span compositional analysis, resolution of unknown (nano)crystal phases, determination of the nanocrystal facets, assessment of ligands bound to the surface, and analysis of the optical properties. All of these characterizations, in turn, require specific advanced tools. The data collected are complemented by computational models to attain a complete picture of a given system. Here, we highlight the best practices for the application of these techniques, also based on the expertise developed in our groups. nanocrystals synthesized in solution comprising an inorganic crystalline core and an organic ligand shell. computational method based on quantum mechanics that provides highly accurate electronic structures and geometries of molecules and bulk materials. comprises the use of electrons in TEM to acquire a diffraction pattern from micro- or nano-objects. this type of synthesis involves the injection of a precursor into a hot mixture comprising a solvent, surfactants, and the remaining precursors. The nucleation and growth of NCs occurs at high temperature after the injection. performed by dispersing MH precursors in polar solvents, which are then injected at room temperature into a mixture of nonpolar solvent and surfactants. The mixing of the two solutions produces an instantaneous condition of supersaturation, which leads to the sudden nucleation of colloidal NCs. a cluster of atoms plus molecules that closely represents a NC characterized in an experiment. The size of this model is such that it can be computed and analyzed with DFT. amphiphilic molecules bound to a nanocrystal’s surface.